Go to Section
- HAART
- Highly Active AntiRetroviral Therapy (for AIDS)
- Habitat
- The type of site where an organism normally lives.
- Habituation
- Haeckel, E.
- Hair cells
- Half-life
- The time needed for (1) half the atoms of a radioactive substance to decay or (2) half the amount of a substance (e.g., a drug) to be metabolized or excreted.
- Haltere
- HAMA
- human antimouse antibodies
- Ham's medium
- Haploid
- Having only a single set of chromosomes (n) as is present in gametes. Also called monoploid.
- Haplotype
- Hardy-Weinberg equilibrium
- Harlequin chromosomes
- Haversian canal
- HDL (high-density lipoprotein)
- Hearing, sense of
- Heart
- [anatomy of human heart ] [ control of human heart ] [ fish heart ] [ frog and lizard hearts ] [ squid hearts ]
- Heat receptors
- Heat transport
- Hedgehog signaling
- HeLa cells
- Helicase
- Helicobacter pylori
- [adaptation to stomach]
- Heliotropism
- Helix-turn-helix proteins
- Helminth
- General term for any member of three groups of parasitic "worms": flukes (trematodes), tapeworms (cestodes), and roundworms (nematodes).
- Helper T cells
- [Discussion] [Interaction with B cells]
- Hemagglutinin
- of influenza virus
- Hematocrit
- Heme
- Hemichordata
- Hemidesmosomes
- Hemizygous
- Genes present in only one copy, not two, in an otherwise diploid cell or individual. Human males are hemizygous for most of the genes on the X chromosome.
- Hemoglobin
- A red, iron-containing protein that transports oxygen and carbon dioxide in the blood of vertebrates and some invertebrates. [More] [sickle-cell] [in different species]
- Hemophilia
- [A, B, C] [Inheritance]
- Hemophilus influenzae
- [vaccine]
- Heparan sulfate
- Heparin
- Hepatic portal system
- Hepatitis B
- HER1 and HER2
- Herbaceous
- Nonwoody.
- Herbicides
- Herbivore
- An animal that eats plants.
- Hereditary angioedema (HAE)
- Heritability
- Herpesviruses
- Hershey, A. D.
- Hertz
- Cycles per second.
- Heterochromatin
- Heterodimer
- Complex of two different proteins.
- Heteroduplex DNA
- Heteroplasmy
- Heterotrophic
- Requiring a supply of organic compounds (food) from the environment. [ More ]
- Heterozygous
- Having two different alleles (e.g., A and a) at the corresponding gene loci on homologous chromosomes.
- Hexapoda (the insects)
- Hexose
- Hippocampus
- Histidine
- Histocompatibility molecules
- [class I] [class II] [minor] [genes that encode them] [structure of HLA-A2]
- Histones
- [ histone acetyltransferases (HATs) ] [ histone deacetylases (HDACs) ]
- HIV, the Human Immunodeficiency Virus
- [how it evades the immune system]
- HLA
- human leukocyte antigen [structures] [genes]
- Homeobox
- A sequence of 180 base pairs which encodes a 60-amino acid homeodomain found in many DNA-binding proteins. Genes containing homeoboxes are found in all eukaryotic genomes.
- Homeostasis
- Maintenance of a relatively constant internal environment (ECF).
- Homeothermic
- Having a constant body temperature above that of the usual surroundings; therefore, "warm-blooded".
- Hominoid
- Group of primates that includes hominids and hominins. [Discussion]
- Homodimer
- Complex of two identical protein molecules.
- Homo habilis
- Homologous
- Showing a fundamental similarity of structure because they have been inherited from a common ancestor. Applied to structures ranging from organs to molecules.
- [illustrated discussion] [chromosome pairs]
- Homoplasmy
- Homozygous
- Having identical alleles (e.g., AA or aa) at the corresponding gene loci on homologous chromosomes.
- Honeybees (Apis mellifera)
- [life history] [honeybee communication]
- Hormesis
- Hormone
- Substance secreted by cells in one part of the body which, after being transported by body fluids, exerts an effect on the activities of cells elsewhere in the body. [of humans] [of insects] [sex hormones] [of plants]
- Horsetails
- Hox gene clusters
- [in Drosophila, mouse, and human]
- HTLV-1
- and adult T-cell leukemia/lymphoma (ATL)
- Hubel, D. H.
- Human Genome Project (HGP)
- Human papilloma virus (HPV)
- [interaction with tumor suppressor genes] [and apoptosis] [vaccine]
- Humus
- hunchback (hb)
- [role of gene in Drosophila segmentation]
- Huntington's disease
- [mutation]
- Hutchinson-Gilford progeria syndrome
- Hyaluronic acid
- Hybrid
- Organism produced by genetically dissimilar parents. It is heterozygous for one or (more often) many pairs of genes.
- Hybridization
- Hydrocarbons
- Hydrogen bond
- [ in
DNA ]
- Hydrolysis
- Decomposition of a substance by the insertion of water molecules between certain of its bonds. Food is digested by hydrolysis.
- Hydronium ion
- Hydrophilic
- Used to describe molecules or molecular groups that are attracted to water and other polar solvents.
- Hydrophobic
- Used to describe molecules or molecular groups that mix poorly with water. Hydrocarbons and fats are hydrophobic. [hydrophobic interactions between macromolecules]
- Hydroxyl group
- Hydroxyl radical
- Hypercholesterolemia, familial
- Hypertension
- Hypertonic solutions
- Hypervariable regions
- Hypoblast
- The layer of the inner cell mass of amniotic embryos which will develop into the yolk sac (endoderm) [Link]. See Epiblast.
- Hypocotyl
- That portion of the shoot of a plant embryo or seedling below the node to which the cotyledons are attached. [View]
- Hypothalamus
- [hormones of]
- Hypothesis
- [testing] [null]
- Hypotonic solutions